Jumat, 21 Oktober 2011

Family Chrysoviridae Virus

Family Chrysoviridae Virus

Chrysoviruses are a group of viruses in the Chrysoviridae family. They are Class III double stranded RNA viruses which infect fungi, in particular Penicillium. Their name is derived from the Greek word chrysos which means yellow-green. The virus particles are non-enveloped and icosohedral with a diameter between 35-40 nm. The genome has three double stranded RNA segments. All have extended highly conserved terminal sequences at both ends

A new double-stranded RNA (dsRNA) virus designated A. fumigatus chrysovirus (AfuCV), belonging to the family Chrysoviridae, has been identified in the filamentous fungus Aspergillus fumigatus. The virus was detected in five of 390 A. fumigatus isolates screened. Analysis of purified dsRNA revealed four distinct species 3560, 3159, 3006 and 2863 base pairs in length (dsRNAs 1-4) which were cloned and sequenced. Each dsRNA contains a single open reading frame (ORF) with short 5' and 3' untranslated regions containing strictly conserved termini. The deduced 1114 amino acid (aa) protein (molecular mass=128 kDa) encoded by the dsRNA1 ORF showed homology to the RNA-dependent RNA polymerase (RdRP) of viruses belonging to the Chrysoviridae. Eight motifs characteristic of RdRPs were identified. The dsRNA2 ORF encodes the putative coat protein subunit (953aa; molecular mass=107 kDa). The dsRNA3 and dsRNA4 ORFs respectively encode putative proteins (891aa, molecular mass=99 kDa) and (847aa, molecular mass=95 kDa), both of which have significant similarity to proteins encoded by comparable chrysovirus dsRNAs. The dsRNA profile, amino acid sequence alignments, and phylogenetic analyses all indicate that AfuCV is a new species within the family Chrysoviridae.

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